﻿// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information
// 
// Licensed to the Apache Software Foundation (ASF) under one or more
// contributor license agreements. See the NOTICE file distributed with
// this work for additional information regarding copyright ownership.
// The ASF licenses this file to you under the Apache License, Version 2.0
// (the "License"); you may not use this file except in compliance with
// the License. You may obtain a copy of the License at
// 
// http://www.apache.org/licenses/LICENSE-2.0
// 
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// 

using System;
using System.Text;
using System.IO;

namespace log4net.Util
{
    /// <summary>A <see cref="StringWriter"/> that can be <see cref="Reset"/> and reused</summary>
    /// <remarks>
    /// <para>
    /// A <see cref="StringWriter"/> that can be <see cref="Reset"/> and reused.
    /// This uses a single buffer for string operations.
    /// </para>
    /// </remarks>
    /// <author>Nicko Cadell</author>
    public class ReusableStringWriter : StringWriter
    {
        /// <summary>Create an instance of <see cref="ReusableStringWriter"/></summary>
        /// <param name="formatProvider">the format provider to use</param>
        /// <remarks>
        /// <para>
        /// Create an instance of <see cref="ReusableStringWriter"/>
        /// </para>
        /// </remarks>
        public ReusableStringWriter(IFormatProvider formatProvider) : base(formatProvider) 
        {
        }

        /// <summary>Override Dispose to prevent closing of writer</summary>
        /// <param name="disposing">flag</param>
        /// <remarks>
        /// <para>
        /// Override Dispose to prevent closing of writer
        /// </para>
        /// </remarks>
        protected override void Dispose(bool disposing)
        {
            // Do not close the writer
        }

        /// <summary>Reset this string writer so that it can be reused.</summary>
        /// <param name="maxCapacity">the maximum buffer capacity before it is trimmed</param>
        /// <param name="defaultSize">the default size to make the buffer</param>
        /// <remarks>
        /// <para>
        /// Reset this string writer so that it can be reused.
        /// The internal buffers are cleared and reset.
        /// </para>
        /// </remarks>
        public void Reset(int maxCapacity, int defaultSize)
        {
            // Reset working string buffer
            StringBuilder sb = this.GetStringBuilder();

            sb.Length = 0;
            
            // Check if over max size
            if (sb.Capacity > maxCapacity) 
            {
                sb.Capacity = defaultSize;
            } 
        }
    }
}
